Lifespan behavioral and neural resilience in a social insect

Analyses of senescence in social species are important to understanding how group living influences the evolution of ageing in society members. Social insects exhibit remarkable lifespan polyphenisms and division of labour, presenting excellent opportunities to test hypotheses concerning ageing and behaviour. Senescence patterns in other taxa suggest that behavioural performance in ageing workers would decrease in association with declining brain functions. Using the ant Pheidole dentata as a model, we found that 120-day-old minor workers, having completed 86% of their laboratory lifespan, showed no decrease in sensorimotor functions underscoring complex tasks such as alloparenting and foraging. Collaterally, we found no age-associated increases in apoptosis in functionally specialized brain compartments or decreases in synaptic densities in the mushroom bodies, regions associated with integrative processing. Furthermore, brain titres of serotonin and dopamine—neuromodulators that could...对社会性物种衰老过程的分析，对于理解群体生活如何影响社会成员的衰老演化进程具有重要意义。社会性昆虫（social insects）展现出显著的寿命多态性（lifespan polyphenisms）与劳动分工（division of labour）特征，为检验衰老与行为相关的假说提供了绝佳的研究契机。其他类群的衰老模式表明，衰老工蚁的行为表现会随大脑功能衰退出现下降。本研究以达氏大头蚁（Pheidole dentata）为模型，发现已完成实验室寿命86%的120日龄小型工蚁，其支撑异亲抚育与觅食等复杂任务的感觉运动功能（sensorimotor functions）并未出现衰退。与此同时，我们未观察到功能特化脑区中出现与年龄相关的细胞凋亡（apoptosis）水平上升，也未发现与整合加工相关的蕈形体（mushroom bodies）区域突触密度出现下降。此外，血清素与多巴胺这两种可发挥……作用的神经调质的脑内含量——